Blackwing - Sirocco the Dawn (TU04-EN003) - Turbo Pack: Booster Four Unlimited

If your opponent controls a monster and you control no monsters, you can Normal Summon or Set this card without Tributing. Once per turn, you can select 1 face-up "Blackwing" monster you control. It gains ATK equal to the total ATK of all face-up "Blackwing" monsters on the field except itself. Monsters other than the selected monster cannot attack the turn you activate this effect.